As far as lifting the left heel, I've always thought of it in the sense that it is lifted, not that you lift it. Allowing the left heel to be taken off the ground naturally by the Pivot, instead of lifting it intentionally, will leave you better off in your Motion IMHO. Personally, my heel doesn't lift, but I attribute that to flexibility instead of an effort to keep it grounded. If the Pivot wants to lift the heel, then let it be lifted. It works for me, but what do I know?
IMHO, lifting the left heel is a great drill for learning the "feel" of a proper pivot. I am re-learning, and using the lift the left heel, Right-Left-Right-Left, drills all the time until I re-learn getting my weight shifted while staying centered. WONDERFUL drill that I now use for every student. Once you have it, I agree, just let it happen...
Kevin
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I could be wrong. I have been before, and will be again.